In a ceremony held at Dallas-Fort Worth Airport in Texas, the hub of the airline, officials from NASDAQ and the airline celebrated the official opening. The ticker symbol is AAL.

Doug Parker, who was chairman and CEO of US Airways and is now CEO of the new airline, said "we will restore AA to the greatest airline in the world," and that as the biggest airline, it should also be the most profitable.

In November, the Department of Justice, which had sued to block the merger to preserve competition in the industry, allowed it to go forward. The new airline agreed to give up slots at seven airports around the country, which will likely go to low-cost airlines like Southwest and JetBlue.

Federal bankruptcy judge Sean Lane gave American approval to exit bankruptcy in late November, allowing the merger to go ahead.